The invention relates generally to call processing techniques for a telecommunications network and, more particularly, to a protocol for completing circuit or packet-switched connections between mobile and other terminals of the telecommunications network.
Within a telecommunications network, a switching system or other type of switching node couples originating and terminating stations for a call. Residing within a typical switching node are first and second software modules, commonly referred to as an originating call handler and a terminating call handler, respectively. The originating call handler handles exchanges of messages with the originating stations while the terminating call handler handles exchanges of messages with the terminating stations. In one configuration thereof, one or both of the originating and terminating stations may be terminals where the call actually originates and/or terminates. In an alternate configuration thereof, one or both of the originating and terminating stations may be trunks which couple the switching node to a next switching node. In either configuration, however, to complete a call involves a series of exchangesxe2x80x94from the originating station to the originating call handler, from the originating call handler to the terminating call handler and from the terminating call handler to the terminating station. The net effect of the various exchanges that are required to complete a call is that the connection protocol for calls is both complex and consumes an excessive amount of resources.
There have been several attempts to simplify the connection protocol for a call. In one such attempt, the originating and terminating call handlers which reside at the switch and which control exchanges with the originating and terminating stations, respectively, were replaced with a single handler which conducted exchanges with both stations. To create such a handler, however, requires explicit knowledge of both the originating and terminating access links. While the resultant handler is able to rapidly conduct exchanges, continued maintenance of the handler is a difficult task. For example, since the various stations are coupled together by the single handler, a software update to one station may require updates to all of the stations which interact with the updated station by way of the single handler.
In any event, use of a central entity that brokers or otherwise oversees the connection between the originating and terminating stations remains a highly inefficient use of resources. It is, therefore, the object of this invention to provide a connection protocol for controlling circuit or packet-switched connections which equally distributes overseeing of the connection between agents of the originating and termination stations.
In one embodiment, the present invention is of a method for establishing a one-way switched connection between a first terminal and a second terminal in which the connection between the first and second terminals is established only when an agent of the first terminal is willing to transmit to an agent of the second terminal and the agent of the second terminal is willing to listen to the agent of first terminal. Preferably, the agent of the first terminal transmits an endpoint address needed to complete the connection between the terminals and, upon acceptance of the endpoint address by the second terminal, the one-way connection between the terminals is established. In alternate aspects thereof, the one-way connection may either be a circuit-switched connection or a packet-switched connection. In further aspects of the one-way circuit-switched connection aspect of the invention, the first terminal may transmit either a nil address or a conference port address to the second terminal. If the agent of the second terminal accepts the nil address, the second terminal will be placed on hold for the first terminal. If the agent of the second terminal accepts the conference port address, the second terminal will enter into a conference call which includes the first terminal.
In another embodiment, the present invention is of a method for establishing a bi-directional connection between a first terminal and a second terminal in which the bidirectional connection between the first terminal and the second terminal is only established when an agent of the first terminal is willing to transmit to an agent of the second terminal, the agent of the second terminal is willing to listen to the agent of the first terminal, the agent of the second terminal is willing to transmit to the agent of the first terminal and the agent of the first terminal is willing to listen to the agent of the second terminal. Preferably, when the agent of the first station is willing to transmit to the agent of the second station, the agent of the first station transmits a first endpoint address which identifies the location of the first station and, when the agent of the second station is willing to transmit to the agent of the first station, the agent of the second station transmits a second endpoint address which identifies the location of the second terminal. Upon the agent of the second terminal accepting the first endpoint address and the agent of the first terminal accepting the second endpoint address, the bidirectional connection between said first and second terminals is established. As before, in alternate aspects of this embodiment, the bi-directional connection may either be a circuit-switched connection or a packet-switched connection.
In still another embodiment, the present invention is of a method for establishing a circuit-switched connection between a first terminal of a telecommunications network and a second terminal of the telecommunications network. The method is commenced by determining if the first connection agent is willing to transmit to the second connection agent. If the first connection agent is willing to transmit to the second connection agent, the first connection agent transmits a first endpoint address for the first terminal to the second connection agent. It is then determined if the second connection agent is willing to listen to the first connection agent. If the second connection agent is willing to listen to the first connection agent, the first endpoint address is used to establish a one-way circuit-switched connection between the first terminal and the second terminal such that the first terminal can talk to the second terminal and the second terminal can listen to the first terminal. In one aspect thereof, it is further determined if the second connection agent is willing to transmit to the first connection agent. If the second connection agent is willing to transmit to the first connection agent, the second connection agent transmits a second endpoint address for the second terminal to the first connection agent. It is then determined if the first connection agent is willing to listen to the second connection agent. If the first connection agent is willing to listen to the second connection agent, the second endpoint address is then used to establish a return circuit-switched connection between the first and second terminals in which the second terminal can talk to the first terminal and the first terminal can listen to the second terminal.
In still yet another embodiment, the present invention is of a switching node for a telecommunications network which includes first and second terminals. The switching node includes a first connection agent for handling exchanges with the first terminal, a second connection agent for handling exchanges with the second terminal and a connection handler for handling exchanges between the first connection agent and the second connection agent. The connection handler transfers an endpoint address for the first terminal from the first connection agent to the second connection agent only if the first connection agent is willing to transmit to the second connection agent and the second connection agent is willing to listen to the first connection agent and transfers an endpoint address for the second terminal from the second connection agent to the first connection agent only if the second connection agent is willing to transmit to the first connection agent and the first connection agent is willing to listen to the second connection agent. In one aspect thereof, the first terminal is a first mobile terminal, the second terminal is a second mobile terminal, the switching node is a mobile switching center and the telecommunications network is a wireless network. In another, the connection handler module resides within a call processing application of the mobile switching center. In still another, a circuit/packet switching module coupled to the first connection agent, the second connection agent and the connection handler, transfers the endpoint address for the first terminal from the first connection agent to the second connection agent and transfers the endpoint address for the second terminal from the second connection agent to the first connection agent in response to instructions issued by the connection handler.